Chapter 5 (Notes) Flashcards
heat shock proteins are upregulated during
high T/stress
eg. chaperonins
chaperonins
help proteins fold correctly
eg. GroEL/GroES in E. coli
thermosomes
hollow balls that proteins fold inside of
cytosol of euk and archaea
protein adaptations
more charged aa –> salt bridges and H-bonding
hydrophobic interiors
lipid adapatations in psychro/thermophiles
psychophiles: more unsat. FA
thermophiles: more sat FA
membrane adaptations of thermophiles
fewer sterols
ether bonds
isoprenes instead of FA; harder to break
monolayer - diglycerol tetraether
big 2 nucleic acid adaptations in thermophiles
special solute 2,3-DPG - changes intracellular ion [ ] (potassium salt of this is a thermostabilizer)
heat-stable DNA binding proteins increase melting temp of DNA
histone like proteins that form nucleosome-like structures to stabilize DNA
other 2 nucleic acid adaptations in thermophiles
tight coiling in pos direction (opposite of normal) by reverse DNA gyrase
more CG bonding b/c triple bond vs. AT double bond
upper temperature of life?
strain 121 - Geogemma barossii in a black smoker hydrothermal (300 degrees C) vent called Finn in Pacific Ocean
strain 121 growth
grows in an autoclave at 121 degrees C g=25 hrs
biostatic at 130 degrees C
strain 121 facts
1 micrometer coccoid with lophotrichous flagellation
reduces Fe(III) ferric to Fe(II) ferrous to form magnetite
barophilic and piezophilic adaptations
more unsat FA to make less likely to gel at high P
pressure-active proteins expressed at high P (porin OmpH)
psychrophilic adaptations (need flexibility in cold)
fewer charged aa
more alpha-helices
cold-adapted proteins (CAPs) –> interact with DNA to serve as a cryoprotectant
sugars “betaine”, glycerol
water activity (aw)
a measure of how much water is available for use
ratio of a solution’s vapor pressure to that of pure water
pure water has an aw of _
1
osmolarity
inversely related to aw
meaure of the number of solute molecules in soln
aquaporin
membrane-cahnnel proteins that allow water to cross the cell memb. faster than diffusion
protect cell from osmotic stress
bacteria need aw levels greater than…
> .91
fungi tolerage aw levels of greater than…
> .86
osmoprotectants - compatible solutes
osmophiles and halophiles achieve osmotic balance with the envir. by producing balancing intracellular concentrations of these
non-toxic low MW organics that counter osmotic pressure from high salt or sugar outside cell
examples of osmoprotectants
sugars, glycerol, glutamate, DMSP
KCl
Trehalose
Trehalose
disaccharide osmoprotectant with high water retention capability
protects membranes from drying
xerophile adaptations (dessication - super dry)
spore formation
extracellular polysaccharides
non-reducing sugars (Trehalose) form “glass/gel” around proteins
endolithic microbes switch metabolic activity on/off
Na circulation in alkaliphiles
sodium motive force in addition to proton motive force
Na+/H+ antiporters to bring protons into the cell
oxygen is a benefit to ______
aerobes - organisms that use it as a TEA to extract energy from nutrients
oxygen is toxic to…
cells that don’t have the enzymes to destroy ROS
eg. anaerobes
ROS
reactive oxygen species
O2+ e- –> superoxide
enzymes that can deal with ROS
superoxide dismutase turns it into hydrogen peroxide
catalase and peroxidase turn hydrogen peroxide into water
______ concentrations control growth and microbial diversity
nutrient
humans often alter microbial ecosystems (aquatic in particular)
eutrophication
sudden infusion of a large amount of a limiting nutrient
leads to bloom of microbes that threatens competing species
how have humans caused nutrient pollution 3 ways
phosphate-containing soaps
nitrogen-containing runoff from farms, lawns, and golf courses
untreated sewage
2 types of O2 usage anaeroes
obligate
aerotolerant
3 types of O2 usage aerobes
obligate
facultative: adjust/switch to anaerobic growth
microaerophile: require O2 in small amounts
steam autoclave
high T high P
PV = nRT
121 degrees C = 250 degrees F
15psi
20 min
filtration
pore sizes of .2mm remove microbial cells but not viruses from soln
samples of 1ml to liters drawn through a membrane filter via vacuum or syringe
air filtration
laminar flow biological safety cabinets
HEPA filters remove 99.9% of airborne material .3 micrometers or larger
phenol coefficient test
compares effectiveness of disinfectants to kill microbes in 10 min
higher coefficient = higher efficacy
disinfectant
kills microbes on inanimate objects
antiseptic
remove pathogens from living tissue
antimicrobial agent
anything that kills or inhibits growth
physical, chemical, or biological
bacteriocidal
kill bacteria
bacteriostatic
inhibits growth of bacteria
sterilize
kills all organisms
sanitize
reduce # of microbes
chemical agents
bleach - Na hypochlorite soln denatures macromolecules
HClO - chlorite
commercial disinfectants
damage proteins, lipids, DNA
phenolics, alcohols, aldehydes, gases
bacteria can develop resistance to disinfectants 3 ways
alter FA synthesis protein that is normally targeted by triclosan
produce membrane-spanning multidrug efflux pumps
form multispecies biofilms - collaborative protection
antibiotics
chemical compounds synthesized by a microbe that kills or inhibits growth of other species
eg. penicillin mimics part of the cell wall to prevent formation - bacteriocidal
3 targets of antibiotics
protein synthesis
DNA replication
cell membranes
biocontrol
the use of one microbe to control the growth of another
probiotics
biocontrol - contain microbes that when eaten, restore balance to intestinal flora
phage therapy
biocontrol - treat infectious disease with a virus targeted to the pathogen
eg. Finalyze hide wash kills E. coli on cattle
virus size range
.02 - .3 micrometers (20-300nm)
virus genome
RNA or DNA
ss or ds
linear or circular
virion
virus particle
have a capsid protein coat
some have membranous envelope, tails/fibers, identifying surface proteins
viruses are ___-specific
host
viral replication general features (4)
attachment and penetration
synthesis of viral genome and proteins
assembly and packaging
release of virions
